Prediction of batch heat transfer coefficients for pseudoplastic fluids ...

CHAPTER 2
R,EVIE\rJ OF B,ACKGROD1m l1ATERIAL
PSEUDO PLASTIC FLUIDS
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wnile Newtonian behavior is only one of many rheological
types, the large majority of fluids h~~dled
industrially
are Newtonian.
Pseudoplastic fluids are second
in i1nportance to the NeHtonians (118)..
The Bingham plas tics
are probably third in importance but many of these have been
treated as pseudoplastics (126).
There are very few industrial
dilatants, and the time dependent and viscoelastic
fluid groups are small 8nd are often treated as pseudoplastics
(7, 118, 120, 121, 126, 128, 179, 186). Pseudoplastic fluids
l.Jere studied in this Hork because of their relative importance.
~1elts a..Yld sol'll'tions of substances Hi th high mole cular
weight are usually pseudoplastic (118, 196) ..
Suspensions
of asymmetrie solids are often in this category. (120, 213).
Typical examples of pseudoplastics are polystyrene, copolymers
of styrene, low and high pressure polyethylene, rubber
modified styrene polymers, and slurries of cement rock in
water (96, 212).
The flm ..! behavior of pseudop1astic fluids is shov.ffi
graphically in Figure 2-1.
At very lov.T a..Yld very high shear
rates the apparent viscosity is a constant, as shown in
curve A.
Thus in these ranges the fluid acts as a Newtonian
fluid. BetvJeen these two extremes., hOl